Justin Thomas withdrew from the PGA Championship on Monday due to a wrist injury, tournament organizers announced.

Kelly Kraft will fill Thomas’ spot in the tournament, which begins with Thursday’s first round.

Thomas won the 2017 PGA Championship, his first career major, by two strokes ahead of runners up Francesco Molinari, Louis Oosthuizen and Patrick Reed.

Thomas explained his absence with a note on his Twitter account Monday afternoon, expressing his deep disappointment in missing the tournament. He tweeted:

"Unfortunately, I will be withdrawing from the 101st PGA Championship at Bethpage Black this week as my wrist is not yet fully healed. Obviously, as a past Champion, this tournament is extra special to me. It consistently has the strongest field in golf and I'm disappointed to not be among those competing this year but I'm optimistic about a return in the near future."

Justin Thomas finished tied for 12th at last month's Masters, but says his wrist is not yet fully healed to play the PGA Championship.(Photo: Michael Madrid, USA TODAY Sports)

Thomas’ best result this season was second at the Genesis Open in February. He also finished third in the Waste Management Phoenix Open and the Sentry Tournament of Champions. He injured his wrist and shoulder while hitting a tree when trying to hit a shot at the Honda Classic in March.

The 26-year-old is coming off a T-12 finish at the Masters where he finished 8-under 280. The winner of nine PGA Tour titles is No. 5 in the Official World Golf Ranking.

Thomas’ withdrawal from the tournament means there will only be 99 of the World Top 100 players playing in the event.